The present invention relates to optical systems and, in particular, it concerns an optical system including a light-guide optical element (LOE) for achieving optical aperture expansion.
Many near-eye display systems include a transparent light-guide optical element (LOE) or “waveguide” placed before the eye of the user, which conveys an image within the LOE by internal reflection and then couples out the image by a suitable output coupling mechanism towards the eye of the user. The output coupling mechanism may be based on embedded partial reflectors or “facets”, or may employ a diffractive pattern. The description below will refer primarily to a facet-based coupling-out arrangement, but it should be appreciated that various features of the invention are also applicable to diffractive arrangements.